 Wyoming Species Account 

Townsend’s Big-eared Bat Corynorhinus townsendii

REGULATORY STATUS USFWS: No special status USFS R2: Sensitive UWFS R4: Sensitive Wyoming BLM: Sensitive State of Wyoming: Nongame Wildlife

CONSERVATION RANKS USFWS: No special status WGFD: NSS3 (Bb), Tier II WYNDD: G4, S2B/S1N Wyoming Contribution: LOW IUCN: Least Concern

STATUS AND RANK COMMENTS Two subspecies of Townsend’s Big-eared Bat (Corynorhinus townsendii), Virginia Big-Eared Bat (C. (formerly Plecotus) t. virginianus) and Ozark Big-eared Bat (C. (formerly Plecotus) t. ingens), were listed as Endangered under the Endangered Species Act (ESA) in 1979 1. Neither subspecies occurs in Wyoming. Townsend’s Big-eared Bat has been assigned both a breeding season and non-breeding season state conservation rank by the Wyoming Natural Diversity Database because of increased extrinsic stressors during hibernation.

NATURAL HISTORY Taxonomy: There are five recognized subspecies of Townsend’s Big Eared Bat. The geographic distribution of these subspecies has previously been called into question by taxonomic authorities 2. The most recent literature indicates that only C. t. townsendii occurs in Wyoming 2-4. Earlier authors also assigned C. t. pallescens throughout much of western North America, including Wyoming 4. Prior to 1992, Townsends Big-eared Bat was included in the genus Plecotus. Phylogenetic evidence based on morphological and genetic differences placed New World Big-eared Bats in the genus Corynorhinus 5. It is important to note that literature from the New World prior to this time refers to Townsend’s Big-eared Bat as P. townsendii. Additionally, the United States Fish and Wildlife Service still uses the genus Plecotus for Virginia Big-eared Bat and Ozark Big- eared Bat. Description: Townsend’s Big-eared Bat is easily identified in the field. The species is medium in size among bat species that occur in Wyoming. As the common name suggests, Townsend’s Big-eared Bat has large, rounded ears ranging from 30–39 mm in length with long, pointed tragi measuring 11– 17 mm. When in torpor or hibernation, the ears may curl back, forming distinctive “rams horns”. The species also has a distinctive nose with large, raised pararhinal glands that form a “U” over

Page 1 of 10  Wyoming Species Account  the top of the snout 3. Dorsal pelage is slate gray with hair tips ranging from cinnamon to black- brown. Ventral pelage is slightly lighter in color and ranges from light slate gray to buff. In many populations, females are slightly larger than males but are otherwise identical in appearance 6. Other large-eared bat species found in Wyoming include Spotted Bat (Euderma maculatum) and Pallid Bat (Antrozous pallidus). Unlike Townsend’s Big-eared Bat, Spotted Bat has black dorsal pelage with three white spots, and Pallid Bat is smaller with inconspicuous pararhinal glands 3. Distribution & Range: Townsend’s Big-eared Bat is widely distributed across the western half of North America from British Columbia to southern Mexico. Wyoming marks the northeastern edge of this distribution, and confirmed breeding has been documented in 5 of the 28 latitude/longitude degree blocks in the state 7. Two subspecies exist in geographically disparate populations in the eastern United States and include Virginia Big-eared Bat, which is found in Kentucky, North Carolina, Tennessee, Virginia, and West Virginia, and Ozark Big-eared Bat, which is found in Arkansas and Oklahoma 1. Changes in distribution may be observed seasonally as the species moves between summer habitat and winter hibernacula. However, Townsend’s Big-eared Bat typically does not undergo long-distance migrations, with movements of approximately 64 km or less reported in portions of its range 6. Habitat: Across its range, Townsend’s Big-eared Bat is found in a variety of xeric to mesic upland habitats ranging from shrublands to woodlands to montane forests 3, 6, 8, 9. At regional and local scales, distribution is limited by suitable roosting habitat. The species is considered a cave obligate, requiring natural caves or cave-like structures, such as abandoned mines, throughout the year. In the summer, day roosts generally include caves and mines, although the species will occasionally use abandoned buildings or large hollow trees 3. Males roost singly in cooler locations, while females congregate in maternity colonies in warmer areas. In winter, Townsend’s Big-eared Bat hibernates in caves and mines. Within hibernacula, the species selects relatively cold locations, often near the entrance or other areas that experience air movement, but may move to warmer locations during extreme cold 6. Phenology: The phenology of Townsend’s Big-eared Bat in Wyoming is largely unknown but is assumed to be similar to other portions of its range. The species hibernates from early fall to early spring. Movements from summer range to winter hibernacula begin in late summer, with individuals arriving at hibernacula by October 3. Reproductive phenology is similarly unknown in Wyoming. In California, mating occurred primarily in the fall but was occasionally documented throughout the winter. Females store sperm over the winter and ovulate upon arousal from hibernation in the spring. A single pup is born following a 40–60 day gestation period. Juveniles are capable of flight at about 3 weeks of age but continue to nurse for up to 6 weeks following birth 3, 6. Diet: Townsend’s Big-eared Bat is strictly insectivorous and primarily consumes small moths in the family Lepidoptera 10.

Page 2 of 10  Wyoming Species Account 

CONSERVATION CONCERNS Abundance: Continental: WIDESPREAD Wyoming: UNCOMMON There are no robust abundance estimates for Townsend’s Big-eared Bat in Wyoming. While the species is widely distributed across Wyoming in a number of different habitat types, Townsend’s Big-eared Bat typically represents a very small proportion of mist-net captures and acoustic recordings, suggesting that the species occurs at low density in the state 11-21. However, Townsend’s Big-eared Bat is commonly detected during hibernacula surveys across Wyoming 22. Population Trends: Historic: UNKNOWN Recent: UNKNOWN There are no robust population trend estimates for Townsend’s Big-eared Bat in Wyoming. However, several authors have reported marked declines in abundance across the western United States over the past several decades 3. It is unknown if similar trends have occurred in Wyoming. Intrinsic Vulnerability: HIGH VULNERABILITY Townsend’s Big-eared Bat is highly vulnerable to extrinsic stressors. The species is considered an obligate of caves and abandoned mines, and it is thought that the distribution and abundance of populations is limited by the presence of suitable, undisturbed roost sites on the landscape 3. Additionally, Townsend’s Big-eared Bat displays high site fidelity, especially at hibernacula and maternity colonies. Given the inherent rarity of these features on the landscape, the species may be unable to find new roost sites should existing sites be lost or degraded 3. Townsend’s Big- eared Bat exhibits low fecundity, with females giving birth to a single pup each year 6. This makes it difficult for populations to recover following declines. Extrinsic Stressors: MODERATELY STRESSED The primary stressor to Townsend’s Big-eared Bat in Wyoming and across its continental distribution is the loss, modification, and disturbance of roosting habitat. Disturbance from visitors to caves and abandoned mines represents a substantial stressor to bats using these structures. During hibernation, even a small number of disturbances can lead to a significant increase in arousal events and energy expenditure that may increase mortality of hibernating bats 9, 23, 24. Townsend’s Big-eared Bat may be more prone to disturbance during hibernation than other bat species because it often selects locations near the entrance of caves and mines. Additionally, the species is reliant upon caves and abandoned mines year round, making it prone to disturbance throughout the year. Abandonment of roosts used as hibernation sites and maternity sites following human disturbance has been documented across the species’ range 3. Townsend’s Big-eared Bat may also be vulnerable to White-Nose Syndrome (WNS). The pathogenic fungus that causes WNS, Pseudogymnoascus destructans (formerly Geomyces destructans), was unintentionally introduced to North America in 2006 25 and has led to large declines of several bat species in eastern North America 25. P. destructans has been documented on a subspecies of Townsend’s Big-eared Bat, Virginia Big-eared Bat, but no mortalities resulting from WNS have been documented in this subspecies to date 26. It is currently unknown if and how WNS will affect Townsend’s Big-eared Bat in the west.

Page 3 of 10  Wyoming Species Account 

KEY ACTIVITIES IN WYOMING State and federal wildlife and land management agencies have taken several actions to protect Townsend’s Big-eared Bat and other bat species from WNS. Specifically, the Black Hills National Forest implemented an adaptive management strategy for caves and abandoned mines to limit the potential for introduction and spread of WNS 27, 28. The Wyoming Game and Fish Department (WGFD) along with the Wyoming Bat Working Group developed “A strategic plan for white-nose syndrome in Wyoming” in 2011 29. This plan is intended to minimize the impacts of WNS if it is detected in Wyoming or adjacent states. To facilitate early detection of the disease, WGFD requires researchers to evaluate all bats captured during research activities for signs of WNS infection using the Reichard Wing-Damage Index 30, and to implement WNS decontamination protocols when handling bats or conducting hibernacula surveys. Beginning in 2012, WGFD personnel placed temperature and humidity loggers in a number of known or suspected hibernacula across Wyoming to determine if climatic conditions at these sites are favorable for growth of P. destructans. Preliminary results suggest that temperature and relatively humidity in known hibernacula could facilitate the growth of the fungus 22, 31. Personnel have also begun collecting swabs of hibernating bats and hibernacula substrates in an effort to assist with early detection of P. destructans. Collectively, WGFD and the Wyoming Natural Diversity Database (WYNDD) have conducted statewide systematic and project-specific surveys for bats since 2008, with numerous, smaller-scale projects occurring prior to this time. In 2011, the WGFD conducted an inventory of forest bats in southeastern Wyoming; Townsend’s Big-eared Bat was not captured during these surveys, but recordings of the species were made at nine sites 32. From 2012 to 2015, WGFD conducted an inventory of cliff and canyon habitats across western Wyoming and captured Townsend’s Big-eared Bat at eight sites and made acoustic recordings of the species at 17 sites 19, 20, 33-35. In 2011, 2012, and 2013, WYNDD conducted a bat inventory across southern Wyoming and captured Townsends Big-eared Bat at five sites made acoustic recordings of the species at 16 sites 11, 12, 17. In 2016, WYNDD made the first documentation of the species at Devils Tower National Monument, and two Townsend’s Big-eared Bats were fitted with radio transmitters and tracked to day roosts at this site. Finally, the WGFD periodically conducts hibernacula surveys at both known and suspected hibernacula throughout the state; Townsend’s Big-eared Bat is frequently encountered at low numbers during these surveys 22.

ECOLOGICAL INFORMATION NEEDS Despite nearly a decade of systematic survey efforts for bats in Wyoming, Townsend’s Big-eared Bat remains understudied in Wyoming. The species would benefit from a better understanding of habitat use, especially in relation to landscape features used during hibernation and at maternity colonies. Additional information is also needed on the amount and degree of disturbance at important roosts and the impact of those disturbances on populations. Information on abundance and population trends is largely unavailable but is important in the face of growing stressors. It is also unknown how WNS might affect Townsend’s Big-eared Bat in Wyoming and across North America.

MANAGEMENT IN WYOMING This section authored solely by WGFD; Nichole L. Bjornlie. Although Townsend’s Big-eared Bat is one of the more commonly encountered bats during hibernacula surveys, little is still known about the majority of wintering locations of the species in Wyoming. Although WNS has

Page 4 of 10  Wyoming Species Account  not been detected in the state, the westward progression of the fungus necessitates the need for these data before it reaches Wyoming. Consequently, priorities will focus on locating and monitoring hibernacula as well as other roost locations (e.g., maternity roosts) to monitor populations and recommend and assist with bat-friendly closures of important caves and mines. In 2016, the WGFD began a project in collaboration with the state of Nebraska to evaluate occurrence, abundance, and reproductive status of bats in eastern Wyoming, which represents an important zone of overlap between eastern and western bat species. Mist-net surveys will continue to implement WNS protocols and assessment in an effort to assist with early detection should the disease reach the state. Habitat assessments will be incorporated with survey efforts to better understand what influences species presence and distribution at a finer scale. In addition to inventory projects, the WGFD, in collaboration with the Wyoming Bat Working Group and other state-wide partners, will implement the North American Bat Monitoring Program that will use acoustic monitoring to assist with state and region-wide assessment of bat trends. Additional priorities will include updating and revising the Conservation Plan for Bats in Wyoming and the Strategic Plan for WNS in Wyoming. Finally, outreach and collaboration with private landowners will remain a priority to ensure conservation of bats and bat habitat.

CONTRIBUTORS Ian M. Abernethy, WYNDD Nichole L. Bjornlie, WGFD Kaylan A. Hubbard, WYNDD

REFERENCES [1] United States Fish and Wildlife Service. (1979) Endangered and threatened wildlife and plants: Listing of Virginia and Ozark Big-eared Bats as endangered species, and critical habitat determination, pp 69206- 69208, Federal Register. [2] Wilson, D. E., and Reeder, D. M., (Eds.) (2005) Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed), Johns Hopkins University Press. [3] Gruver, J. C., and Keinath, D. A. (2006) Townsend's Big-eared Bat (Corynorhinus townsendii): a technical conservation assessment, USDA Forest Service, Rocky Mountain Region. [4] Piaggio, A. J., and Perkins, S. L. (2005) Molecular phylogeny of North American long-eared bats (Vespertilionidae : Corynorhinus); inter- and intraspecific relationships inferred from mitochondrial and nuclear DNA sequences, Molecular Phylogenetics and Evolution 37, 762-775. [5] Frost, D. R., and Timm, R. M. (1992) Phylogeny of plecotine bats (Chiroptera: 'Vespertilionidae'): summary of the evidence and proposal of a logically consistent taxonomy, American Museum Novitates, 1-16. [6] Kunz, T. H., and Martin, R. A. (1982) Plecotus townsendii, Mammalian Species, 1-6. [7] Orabona, A., Rudd, C., Grenier, M., Walker, Z., Patla, S., and Oakleaf, B. (2012) Atlas of birds, mammals, amphibians, and reptiles in Wyoming, p 232, Wyoming Game and Fish Department Nongame Program, Lander, WY. [8] Adams, R. A. (2003) Bats of the Rocky Mountain West: Natural History, Ecology, and Conservation, University Press of Colorado, Boulder, Colorado. [9] Hester, S. G., and Grenier, M. B. (2005) A conservation plan for bats in Wyoming, Wyoming Game and Fish Department Nongame Program, Lander, WY. [10] Ober, H. K., and Hayes, J. P. (2008) Prey selection by bats in forests of western Oregon, Journal of Mammalogy 89, 1191-1200. [11] Abernethy, I. M., Andersen, M. D., and Keinath, D. A. (2012) Bats of southern Wyoming: distribution and migration year 2 report. Prepared for the USDI Bureau of Land Management by the Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming. [12] Abernethy, I. M., Andersen, M. D., and Keinath, D. A. (2014) Bats of southern Wyoming: distribution and migration year 3 report. Prepared for the USDI Bureau of Land Management by the Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming.

Page 5 of 10  Wyoming Species Account 

[13] Abernethy, I. M., and Keinath, D. A. (2015) Bats of northeastern Wyoming. Report prepared for the USDI Bureau of Land Management - Wyoming State Office by the Wyoming Natural Diversity Database - University of Wyoming, Laramie, Wyoming. [14] Abernethy, I. M., Andersen, M. D., and Keinath, D. A. (2015) Bats of Wyoming: distribution and migration year 4 report. Prepared for the USDI Bureau of Land Management by the Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming. [15] Abernethy, I. M., and Keinath, D. K. (2016 In preparation) Bats of northeastern Wyoming. Report prepared of the USDI Bureau of Land Management Wyoming State Office by the Wyoming Natural Diversity Database University of Wyoming, Laramie, Wyoming. [16] Abernethy, I. M., and Keinath, D. K. (2016 In Preparation) Bats of Wyoming: distribution and migration year 5 report. Prepared for the USDI Bureau of Land Management by the Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming. [17] Griscom, H. R., Andersen, M. D., and Keinath, D. A. (2012) Bats of southern Wyoming: Distribution & Migration. Year 1 report. Prepared for the USDI Bureau of Land Management by the Wyoming Natural Diversity Database, University of Wyoming, Laramie, Wyoming. [18] Griscom, H. R., and Keinath, D. A. (2012) Inventory and status of bats at Devils Tower National Monument, p 34, Report prepared for the USDI National Park Service by the Wyoming Natural Diveristy Database - University of Wyoming, Laramie, WY. [19] Abel, B., and Grenier, M. (2012) Inventory of Bats in Forests of Southeastern Wyoming: Acoustic Surveys, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Grenier, M. B., Abel, B., and Cudworth, N., Eds.), pp 155-181, Wyoming Game and Fish Department. [20] Abel, B., and Grenier, M. (2012) Inventory of Bats in Forests of Southeastern Wyoming: Mist Netting, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Grenier, M. B., Abel, B., and Cudworth, N., Eds.), pp 125-154, Wyoming Game and Fish Department. [21] Abel, B., and Grenier, M. (2013) Inventory of Bats in Cliffs and Canyons of Western Wyoming, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Orabona, A., Ed.), pp 234-265, Wyoming Game and Fish Department. [22] Beard, L. (2015) Surveillance of hibernating bats and environmental conditions at caves and abandoned mines in Wyoming, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Orabona, A. C., and Rudd, C. K., Eds.), pp 163-193, Wyoming Game and Fish Department. [23] Boyles, J. G., and Brack, V., Jr. (2009) Modeling survival rates of hibernating mammals with individual based models of energy expenditure, Journal of Mammalogy 90, 9-16. [24] Thomas, D. W. (1995) Hibernating bats are sensitive to nontactile human disturbance, Journal of Mammalogy 76, 940-946. [25] Frick, W. F., Pollock, J. F., Hicks, A. C., Langwig, K. E., Reynolds, D. S., Turner, G. G., Butchkoski, C. M., and Kunz, T. H. (2010) An Emerging Disease Causes Regional Population Collapse of a Common North American Bat Species, Science 329, 679-682. [26] White-nose Syndrome.org. (2015) White-nose Syndrome.org A coordinated response to the devastating bat disease, http://whitenosesyndrome.org/. [27] USDA Forest Service Rocky Mountain Region. (2013) Environmental Assessment for cave and abandoned mine management for white-nose syndrome. [28] USDA Forest Service Black Hills National Forest. (2013) Decision notice & finding of no significant impact Cave and abandoned mine management for white-nose syndrome. [29] Abel, B., and Grenier, M. (2011) A strategic plan for White-nose Syndrome in Wyoming, p 27, Wyoming Game and Fish Department, Lander, Wyoming. [30] Reichard, J. D., and Kunz, T. H. (2009) White-nose syndrome inflicts lasting injuries to the wings of little brown myotis (Myotis lucifugus), Acta Chiropterologica 11, 457-464. [31] Beard, L. (2016) Surveillance of Hibernating Bats and Environmental Conditions at Caves and Abandoned Mines in Wyoming, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Orabona, A. C., Ed.), pp 97-113, Wyoming Game and Fish Department. [32] Cudworth, N., Johnson, S., and Grenier, M. (2011) Inventories of Forest Bats in Northeastern Wyoming: Mist Netting, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Grenier, M. B., Ed.), pp 119-145, Wyoming Game and Fish Department. [33] Yandow, L., and Grenier, M. (2014) Inventory of Bats Associated with Cliff and Canyon Habitats of Western Wyoming, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual

Page 6 of 10  Wyoming Species Account 

Completion Report (Orabona, A. C., and Cudworth, N., Eds.), pp 253-284, Wyoming Game and Fish Department. [34] Yandow, L., and Beard, L. (2015) Inventory of Bats Associated with Cliff and Canyon Habitats of Eastern Wyoming, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Orabona, A. C., and Rudd, C. K., Eds.), pp 133-162, Wyoming Game and Fish Department. [35] Beard, L. (2016) Inventory of Bats Associated with Cliff and Canyon Habitats of Eastern Wyoming, In Threatened, Endangered, and Nongame Bird and Mammal Investigations: Annual Completion Report (Orabona, A. C., Ed.), pp 115-141, Wyoming Game and Fish Department.

Page 7 of 10  Wyoming Species Account 

Figure 1: A Townsend’s Big-eared Bat in Wyoming. (Photo courtesy of Robert J. Luce, WGFD)

Figure 2: North American range of Corynorhinus townsendii. (Map from: Patterson, B. D., et al. (2007) Digital Distribution Maps of the Mammals of the Western Hemisphere, version 3.0, NatureServe, Arlington, Virginia.)

Page 8 of 10  Wyoming Species Account 

Figure 3: Photo not available.

Figure 4: Range and predicted distribution of Corynorhinus townsendii in Wyoming.

Page 9 of 10  Wyoming Species Account 

Figure 5: A captured Townsend’s Big-eared Bat in hand showing the distinctive face and ears. (Photo courtesy of Leah H. Yandow, WGFD)

Page 10 of 10